I. Field of the Invention
The subject matter disclosed herein relates to determining wireless transmitter almanac information to transmit to a mobile station, and more particularly to basing such determinations on expected contributions of one or more wireless transmitters to a future navigation operation for the mobile station.
II. Background
The position of a mobile station, such as a cellular telephone, may be estimated based on information gathered from various systems. One such system may comprise a Global Navigation Satellite System (GNSS), which is one example of a satellite positioning system (SPS). SPS systems such as GNSS may comprise a number of space vehicles (SV) orbiting the earth. Another example of a system that may provide a basis for estimating the position of a mobile station is a cellular communication system comprising a number of terrestrial wireless transmitters/receivers, often referred to as “base stations,” to support communications for a number of mobile stations. A further example of a system that may provide a basis for estimating the position of a mobile station is a wireless network compatible with one or more of the Institute of Electrical and Electronics Engineers (IEEE) 802.11 wireless local access network (WLAN) standards, which may also be referred to as a Wi-Fi network. Such a network may include wireless transmitters/receivers often referred to as “access points,” for example.
A position estimate, which may also be referred to as a position “fix”, for a mobile station may be obtained based at least in part on distances or ranges measured from the mobile station to one or more wireless transmitters, and also based at least in part on knowledge of the locations of the wireless transmitters. Such transmitters may comprise SVs in the case of an SPS, terrestrial base stations in the case of a cellular communications system, or Wi-Fi/802.11x access or points or other beacon transmitters, for example.